Atmospheric Sciences 370 Observing Systems January 2012
ASOS: Automated Surface Observing System: Backbone Observing System in the U.S.
ASOS Located at primary and secondary airports Sponsored by the FAA and NWS High quality instrumentation that is well maintained and calibrated. Reported in METAR format (more later)
Hydrothermograph
Precipitation Gauges
Laser Weather Identifier
Acoustic Anemometer
Anemometer Wind Vane Still used in many systems
Laser Ceilometer
The ASOS Freezing Rain Sensor uses an ultrasonically vibrating probe to detect the presence of icing conditions. The vibrating frequency of the probe decreases with the accumulation of ice.
Lightning Sensor Visibility Sensor
Full ASOS system in Arizona
METAR Format ASOS data (and airport observations worldwide) are transmitted in METAR format. Name came from the French words, MÉTéorologique ("Weather") Aviation Régulière ("Routine"). Example: KSEA Z 11008KT 10SM FEW050 SCT070 OVC090 09/03 A2879 RMK AO2 SLP T Will learn more about it in Lab
Observing Heights (ASOS and most official obs) Temperature and dew point (2-m) Wind speed and direction (10-m)
Other Surface Networks Bureau of Land Management RAWS Agrimet PAWS Department of Ecology Puget Sound Clean Air BC Hydro BC Olympics Weather Underground Many more!
NWNet: Regional Real-Time Collection of Over 70 Networks Over the Pacific Northwest
Oklahoma Mesonet
Networks of Networks UW: We collect data from about 70 networks in real time over NW Mesowest: Collects about 100 networks over the western third of U.S. Madis: national collection of mesonets
Marine Reports
Ocean and Lake Weather Buoys Anchored
Drifting Buoys Wind Pressure
Coastal Marine (CMAN) Reports from the Coast Guard
Northwest Buoy and CMAN Locations
Ship Reports: Marine VOS Program Volunteers Observers--generally 6-hourly reports Highly variable quality and frequency
Satellite Microwave Scatterometer Winds
QuickScat Satellite Bounces microwaves off the ocean surface Capillary waves dependent on wind speed and directon
Upper Air Data
Radiosonde
Radar Wind Profiler and RASS (Radio Acoustic Sounding System)
Seattle Profiler/RASS
Profiler Locations
ACARS: Aircraft Observations Generally on wide-body aircraft Aircraft Communications Addressing and Reporting System
New Satellite Observing Capabilities
Cloud and Water Vapor Track Winds Based on Geostationary Weather Satellites
Satellite Temperature and Humidity Soundings
GOES sounder unit
GPS Sounding A constellation of GPS satellites orbit the earth. A collection of other satellites can receive the GPS signal By measuring the delay in time as the GPS signal is bent by the earth’s atmosphere, one can acquire density information that can be used to create temperature and humidity soundings. Can do this with fixed receivers on earth or with receivers on satellites--the COSMIC project.
Typical Observation Errors at the Surface (Important when doing analyses!) Sea Level Pressure –Low-Elevation land stations +-.5 mb –Ships mb Temperature: +-1C Wind Speed: knots, very light winds often a problem—especially for classical anomemters. Relative Humidity: +-10%
Typical Radiosonde Errors Geopotential heights: –700 mb (hPa): 5-10 m –500 mb m –300 mb m –100 mb m Temperature: +-0.5C Wind speed: +-5%,+-10 degrees
Terminology Direct versus Indirect observations –Direct: measurement at the location of the instrument –Indirect: remotely sensed using radiation measurements Active versus passive remote sensing –Active: instrument emits radiation, analyzes return –Passive: analyzes incoming natural radiation